From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=91.218.175.216 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793678512; b=j5HQPuTDM1SKAQir5mXjrWNau1QomDphwe/XEJ8bn2Z6d8l6xCjvQQItNQ28UKq79ZwY a110+I/q8vkczh9VCfZhfhilu8+/+//6TeWGUgEBwVtwxYxpDycNkr9mnbNn6trywTR3H lBy/Z925YqI4JSj/DmMHlxpgY3YkauGh2E9wvn1ElqiuQxX5rLs6xcTFMrdyuiDxXDRMj sWRzAQs+QPnyLkEkHm0mZHb/IqfbKyhpVtjOhfLGGkWqosjj3iKZ+4gmJKfFfDYqEp1b+ OYSxpLmdI4Ih6OARXPbGWA2IPTHi0wm18a0+ei+6/sI2ODwVNXk3wET6PsiVa3l36rw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793678512; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:Content-Type:Mime-Version:Subject:From: In-Reply-To:Date:Cc:Content-Transfer-Encoding:Message-Id:References: To:X-Mailer; bh=lDb7VF7t9vCGYbcoBtIdF6dRw3MWvJEbXZ5PMZISlw8=; b=NHUiuIlQ7ockjPipfZH2fzHyc3hzLKLOjtmPMikFh5F0y1/gXX3TMmla9ZtKUzQstRih gaRHFv1a6JHITJc4h/akyMhLfh0ZZY9NXYGCaFfaTUjB5Rb0EICU85XqtBhYKQt2+NKNy 4Yuj2BePwsHTwPyqK4sznTt3x1WHIboriqf/B0vRjNUqrqRgpcZ87mahgoTxQ6OIYrDns zyDBPNaxlmk44O5eTgiivJwGqBcniWRKfW/WLddNsYE3WgfNWLF2YmGFhEyV8S2TGORq9 GxNkPhAVg0EfznE7k5lJGDaqV4OCTSppsYhG3/WvFQY7pWAKLiA2SMxsrLKDCIfBUrw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=mkciFVIq; arc=none smtp.remote-ip=91.218.175.216 Received: from mta0.migadu.com (out-216.mta0.migadu.com [91.218.175.216]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DEF47606A324 for ; Tue, 3 Nov 2026 04:01:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org DEF47606A324 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=mkciFVIq X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=CKEHs2xNjn3vFUKXk/OC1dgxFsocWFipvyVq/CmrhPw=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1793678508; v=1; x=1794283308; b=mkciFVIqfGgD8r4GUzUx/IMdlICBgx1UnRaGabM3UodtroGDLhWeiFlH/0shEeRCZGP5IB92 06thgCYP1xhGDvEoArNEuo+ZSvUlgpHl6Lnk9yZfhdVp/+l5+caYDg1VrFQ9lN820ojB4KYhvkg gcPXLyqFh4T7yntjinwdzxZY= X-Envelope-To: linux-kernel@vger.kernel.org Received: by mta11.migadu.com with ESMTPS id 54dd4c98615b8fc8; Tue, 03 Nov 2026 04:01:48 +0000 X-Mizu-Trace-ID: 54dd4c98615b8fc8 X-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset=utf-8 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3901.200.71.1.16\)) Subject: Re: [PATCH] riscv: mm: Add KASAN shadow mapping to flush_cache_vmap() From: Muchun Song In-Reply-To: <20261102134422.610837-1-alitariq45892@gmail.com> Date: Tue, 3 Nov 2026 12:01:27 +0800 Cc: Paul Walmsley , Palmer Dabbelt , Albert Ou , linux-riscv@lists.infradead.org, Alexandre Ghiti , Vivian Wang , Yunhui Cui , Mike Rapoport , David Hildenbrand , kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Message-Id: <63411FA9-C16A-4E40-8C3C-13C58FB844A0@linux.dev> References: <20261102134422.610837-1-alitariq45892@gmail.com> To: Ali Tariq X-Mailer: Apple Mail (2.3901.200.71.1.16) > On Nov 2, 2026, at 21:44, Ali Tariq wrote: >=20 > flush_cache_vmap() sets a per-CPU flag, and a kernel page fault > that finds the flag set gets an sfence.vma and a retry. > flush_cache_vmap() only sets the flag for vmalloc, module and vmemmap > ranges. kasan_populate_vmalloc() maps new shadow pages and calls > flush_cache_vmap() on the shadow range, so no flag gets set. > For vmap()-style areas, kasan_unpoison_vmalloc() writes > the new shadow right away. If the CPU hasn=E2=80=99t seen the new = entry yet, > the store faults, and since there is no flag set, the kernel crashes. >=20 > [ 0.675216] Unable to handle kernel paging request at virtual = address fffffff7c009a000 > Current swapper/0 pgtable: 4K pagesize, 39-bit VAs, = pgdp=3D0x0000000004504000 > [fffffff7c009a000] pgd=3D000000009ff6e001, p4d=3D000000009ff6e001, = pud=3D000000009ff6e001, pmd=3D00000000400e7401, pte=3D00000000403cb0e7 > status: 0000000200000120 badaddr: fffffff7c009a000 cause: = 000000000000000f > __memset+0x60/0xfe > kasan_unpoison+0x26/0x4e > __kasan_unpoison_vmalloc+0x20/0x2e > __get_vm_area_node+0x1c6/0x276 > get_vm_area_caller+0x52/0x84 > vmap+0xf0/0x264 > dma_common_contiguous_remap+0xa0/0xd0 > atomic_pool_expand+0xb6/0x310 > __dma_atomic_pool_init.isra.0+0xf6/0x1c0 > dma_atomic_pool_init+0xf6/0x1aa > do_one_initcall+0x134/0x928 > kernel_init_freeable+0x532/0x60a > kernel_init+0x28/0x162 > ret_from_fork_kernel+0x82/0x94c > ret_from_fork_kernel_asm+0x16/0x18 >=20 > The PTE is valid, so the mapping was in place when the CPU faulted. >=20 > Tested on Orange Pi RV2: without this patch 2 of 30 boots crashed, > with it 50 of 50 booted. >=20 > Add the KASAN shadow region to the ranges for which flush_cache_vmap() > calls mark_new_valid_map(), as commit 4edd70ee6a7d = ("mm/sparse-vmemmap: > flush_cache_vmap() after hotplugging vmemmap") did for vmemmap. >=20 > Fixes: 503638e0babf ("riscv: Stop emitting preventive sfence.vma for = new vmalloc mappings") > Signed-off-by: Ali Tariq Acked-by: Muchun Song Thanks.